244 research outputs found
Antimicrobial and antioxidant potentials of essential oil and acetone extract of Myristica fragrans Houtt. (aril part)
The antifungal, antibacterial, and antioxidant potentials of essential oil and acetone extract were carried out by different techniques. In poison food medium method, the essential oil showed complete zones of inhibition against Fusarium graminearum at the all tested doses. For other tested fungi and bacteria, they gave good to moderate zone inhibition. The antioxidant activity was evaluated by measuring peroxide, thiobarbituric acid and total carbonyl values of rapeseed oil at fixed time intervals. Both the extract and essential oil showed strong antioxidant activity in comparison with butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). In addition, their inhibitory action in linoleic acid system was studied by monitoring peroxide concentration in emulsion during incubation. The results were well correlated with above values. Their radical scavenging capacity was carried out on 2,2′-diphenyl-1-picrylhydracyl (DPPH) radicalm, and they showed strong scavenging activity in comparison with synthetic antioxidants. Their reducing power was also determined, which also proved strong antioxidant capacity of essential oil and extract. Gas chromatographic-mass spectroscopy studies on essential oil resulted in the identification of 49 components representing 96.49% of the total amount, and the major component was sabinene (20.22%), followed by terpinen-4-ol (12.08%), safrole (10.32%), α-pinene (9.7%), β-phellandrene (6.56%), and γ-terpinene (5.93%). The acetone extract showed the presence of 23 components representing 71.66% of the total amount. The major components were isocroweacin (18.92%), elemicin (17.68%), methoxyeugenol (8.13%), linoleic acid (4.12%), dehydrodiisoeugenol (4.06%), palmitic acid (2.8%), and trans-isoeugenol (2.76%). © 2005 Institute of Food Technologists.Fil: Singh, Gurdip. Deen Dayal Upadhyay Gorakhpur University India; IndiaFil: Marimuthu, P.. Deen Dayal Upadhyay Gorakhpur University India; IndiaFil: De Heluani, Carola S.. Universidad Nacional de Tucumán; ArgentinaFil: Catalan, Cesar Atilio Nazareno. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentin
Critical wave-packet dynamics in the power-law bond disordered Anderson Model
We investigate the wave-packet dynamics of the power-law bond disordered
one-dimensional Anderson model with hopping amplitudes decreasing as
. We consider the critical case ().
Using an exact diagonalization scheme on finite chains, we compute the
participation moments of all stationary energy eigenstates as well as the
spreading of an initially localized wave-packet. The eigenstates
multifractality is characterized by the set of fractal dimensions of the
participation moments. The wave-packet shows a diffusive-like spread developing
a power-law tail and achieves a stationary non-uniform profile after reflecting
at the chain boundaries. As a consequence, the time-dependent participation
moments exhibit two distinct scaling regimes. We formulate a finite-size
scaling hypothesis for the participation moments relating their scaling
exponents to the ones governing the return probability and wave-function
power-law decays
Effect of nonlinearity on the dynamics of a particle in dc field-induced systems
Dynamics of a particle in a perfect chain with one nonlinear impurity and in
a perfect nonlinear chain under the action of dc field is studied numerically.
The nonlinearity appears due to the coupling of the electronic motion to
optical oscillators which are treated in adiabatic approximation.
We study for both the low and high values of field strength. Three different
range of nonlinearity is obtained where the dynamics is different. In low and
intermediate range of nonlinearity, it reduces the localization. In fact in the
intermediate range subdiffusive behavior in the perfect nonlinear chain is
obtained for a long time. In all the cases a critical value of nonlinear
strength exists where self-trapping transition takes place. This critical value
depends on the system and the field strength. Beyond the self-trapping
transition nonlinearity enhances the localization.Comment: 9 pages, Revtex, 6 ps figures include
Contribution of Autonomic Reflexes to the Hyperadrenergic State in Heart Failure
Heart failure (HF) is a complex syndrome representing the clinical endpoint of many cardiovascular diseases of different etiology. Given its prevalence, incidence and social impact, a better understanding of HF pathophysiology is paramount to implement more effective anti-HF therapies. Based on left ventricle (LV) performance, HF is currently classified as follows: (1) with reduced ejection fraction (HFrEF); (2) with mid-range EF (HFmrEF); and (3) with preserved EF (HFpEF). A central tenet of HFrEF pathophysiology is adrenergic hyperactivity, featuring increased sympathetic nerve discharge and a progressive loss of rhythmical sympathetic oscillations. The role of reflex mechanisms in sustaining adrenergic abnormalities during HFrEF is increasingly well appreciated and delineated. However, the same cannot be said for patients affected by HFpEF or HFmrEF, whom also present with autonomic dysfunction. Neural mechanisms of cardiovascular regulation act as "controller units," detecting and adjusting for changes in arterial blood pressure, blood volume, and arterial concentrations of oxygen, carbon dioxide and pH, as well as for humoral factors eventually released after myocardial (or other tissue) ischemia. They do so on a beat-to-beat basis. The central dynamic integration of all these afferent signals ensures homeostasis, at rest and during states of physiological or pathophysiological stress. Thus, the net result of information gathered by each controller unit is transmitted by the autonomic branch using two different codes: intensity and rhythm of sympathetic discharges. The main scope of the present article is to (i) review the key neural mechanisms involved in cardiovascular regulation; (ii) discuss how their dysfunction accounts for the hyperadrenergic state present in certain forms of HF; and (iii) summarize how sympathetic efferent traffic reveal central integration among autonomic mechanisms under physiological and pathological conditions, with a special emphasis on pathophysiological characteristics of HF
Trazabilidad de Procesos Scrum
La trazabilidad es considerada en metodologías ágiles como un aspecto fundamental a estudiar para desarrollar sistemas de calidad. Sin embargo, los procesos ágiles ocurren en entornos donde no es frecuente encontrar un documento de especificación de requerimientos, no siendo posible aplicar técnicas clásicas de trazabilidad. En consecuencia, en este trabajo se propone un modelo de trazabilidad basado en las prácticas de Scrum. El objetivo principal del modelo es representar trazas existentes entre los artefactos generados durante procesos Scrum. La propuesta es especializada y ejemplificada siguiendo la documentación del proceso de desarrollo de Moodle.Sociedad Argentina de Informática e Investigación Operativa (SADIO
Trazabilidad de Procesos Scrum
La trazabilidad es considerada en metodologías ágiles como un aspecto fundamental a estudiar para desarrollar sistemas de calidad. Sin embargo, los procesos ágiles ocurren en entornos donde no es frecuente encontrar un documento de especificación de requerimientos, no siendo posible aplicar técnicas clásicas de trazabilidad. En consecuencia, en este trabajo se propone un modelo de trazabilidad basado en las prácticas de Scrum. El objetivo principal del modelo es representar trazas existentes entre los artefactos generados durante procesos Scrum. La propuesta es especializada y ejemplificada siguiendo la documentación del proceso de desarrollo de Moodle.Sociedad Argentina de Informática e Investigación Operativa (SADIO
Trazabilidad de procesos ágiles: un modelo para la trazabilidad de procesos scrum
La trazabilidad es considerada en metodologías ágiles como un aspecto esencial a incorporar para la producción de software de calidad. Sin embargo, los procesos de desarrollo ágiles en contraposición a los procesos de desarrollo “pesados”, no permiten la aplicación directa de las técnicas de trazabilidad tradicionales. En consecuencia, es fundamental desarrollar modelos que permitan trazar los requerimientos bajo el enfoque de los métodos ágiles.
En este trabajo se aborda esta problemática centrada en la metodología ágil Scrum. El modelo propuesto es desarrollado con el objetivo de brindar soporte a las siguientes preguntas de competencia: i) ¿Qué eventos originaron un artefacto en particular?; ii) ¿Qué requerimientos guiaron la generación de tal artefacto?; ¿Quiénes son los participantes involucrados en un evento dado? Las respuestas a estar preguntas asistirían las tareas de trazabilidad en proyectos ágiles tales como: Stakeholders con Requerimientos, User Stories con Versiones y Requerimientos con Requerimientos.WIS - X Workshop ingeniería de softwareRed de Universidades con Carreras en Informática (RedUNCI
Trazabilidad de Procesos Scrum
La trazabilidad es considerada en metodologías ágiles como un aspecto fundamental a estudiar para desarrollar sistemas de calidad. Sin embargo, los procesos ágiles ocurren en entornos donde no es frecuente encontrar un documento de especificación de requerimientos, no siendo posible aplicar técnicas clásicas de trazabilidad. En consecuencia, en este trabajo se propone un modelo de trazabilidad basado en las prácticas de Scrum. El objetivo principal del modelo es representar trazas existentes entre los artefactos generados durante procesos Scrum. La propuesta es especializada y ejemplificada siguiendo la documentación del proceso de desarrollo de Moodle.Sociedad Argentina de Informática e Investigación Operativa (SADIO
Dynamics of an electron in finite and infinite one dimensional systems in presence of electric field
We study,numerically, the dynamical behavior of an electron in a two site
nonlinear system driven by dc and ac electric field separately. We also study,
numerically, the effect of electric field on single static impurity and
antidimeric dynamical impurity in an infinite 1D chain to find the strength of
the impurities. Analytical arguments for this system have also been given.Comment: File Latex, 8 Figures available on reques
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